Gnar, adjustable play style.

I think it would make it interesting if his time in each form was adjusted based on your AD and your HEALTH. A player building tank will be mega gnar more often and for longer. A player building damage will be Mini Gnar for longer. This way you can better provide your team with what they need in a game.

Also he could use more incentive to stay in mini form... i.e. an ULT for that form too.